Microphone for Video Camera

Gil video interviewed three guys for our church planting conference. The video quality was ok, but the audio was fair. We would like to improve it. There is an 1/8" mic jack on the camera.

I was looking at a couple of shotgun mics at Bestbuy.com:

Sima Univeral Zoom Mic $56.99

Sony Gun Zoom $69.99

And a wireless:

Sony Wireless $149.99

I know a little about this stuff. Does anybody else know anything about this? I think it would at least be worth the zoom mic price to at least try to get some better audio.